Apparatus for burning liquid fuel



Oct. 18, 1.938. R.- M. SHERMAN ET AL APPARATUS FOR BURNING LIQUID FUELFiled Deo. '27, 1955 4 Sheets-Sheet l mmA mm. .WWU

Oct. 18, 1938. R. M. SHERMAN ET Al.

APPARATUS FOR BURNING LIQUID FUEL Filed Dec. 27, 1955 4 Sheets-Sheet 2 vInvezzibm: Meagan M ffies/www,

Jalan Cavesftg,

@9M/wlw m Oct. 18, 1938. R. M. SHERMAN T AL y'2,133,485

" APARATUS FOR BURNING LIQUIDFUEL 4 sheets-Sheet 3` Filed Dec. 2'7,i1935' aeom eRJYeuaaamaaa;

Oct. 18, 1938. R, M, SHERMAN IET AL 2,133,485

APPARATUS FOR BURNING LIQUID FUEL Filed 1396.27, 1935 4 sheets-sheet 4E199. /7 49 l E910.

//////\ j A I Patented oa. is, 193s 'PATENT OFFICE s f '.asumn Miyshemm,Glastonbury, R. Neumann,

Carlberg and George ford,I Conn., alsignora Burner Corporation,

ration of AConnecticut mi mm West Bartto The Silent G lo'w Oil Hartford,Conn.. a com- 1 prueauon Decanter zr, 1935, sensi No. 56,334

14 claims.' (CL 15S-1s) This invention relatesto apparatus for burni ingliquid fuel (herein referred to forv descriptivefpurposes as oil). anddeals more particularly with burners of the so-called gun type.

The invention has amongotherobiects to improve conditions` of combustionand more particularly through the method of controlling and applying theair supply -for commingling with the oil, to increase the efilciencyin`\respect to both combustion a'nd oil and power consumptio tosimplify' and improve the mechanical and electrical construction, toconserve the heat imparted to thev combustion chamber, to reduce cost ofmanufacture and provide mechanical compactness, and `to provide sch .anarrangement and assemblage `of parts as to facilitate and simplifyservicing requirements.

These and other objects of the invention will 'y be best understood byreference to the following description when taken in connection with theaccompanying illustration,l while itsscope will be more particularlypointedout inthe appended claims.

In'the drawings: Y Fig'. 1 is an elevation, partlyin centrallongitudinal section, showing' a burner embodying one form of theinvention;

Fig. 2 is a rear elevation of the burner shown withinthe inside surfacesof the walls Il of the in Fig. 1;

Flg. 3 is afront elevation o f the sameburner in section, on the line l-3 in Fig. 1;

Fig. 4 is a detail in section showing the elecf trical connections tothe sparking electrodes;

Fig. 5 is a rear elevation of the main vsupporting casing shown in Fig.1, together with its supporting standard but with the working unitremoved;

Fig. 6 isa section, in plan view, of the-main supporting casing,"on thelin'e 8-'46 in Fig. 5; v' -Flg 7 is a side elevation of the workingparts assembled as a' unitand shown as removed from the casing;

Fig. 8 is a section,.taken on the line'l-C in.

Fig."3, showing one of the motor supporting lugs;

Fig. 9 is a side `elevation of the air impeller fan with the bladesclosed. ishowing the relation of the fan u lthe-'motor end.nurounamgwalls f'of theconduit;

50 blades open;

` Fig'. 10 'is a deelevation showing the .]5 l`g.` 11 is a frontelevation in partial section' showing the air fan with the blades inclosed end;4 andk position looking''fr-oniy the open or air enteringFig. 12 is elevation showing the air fan which is shown by tricalconnections;

looking from the air delivery `side, also with the blades in `closedposition.

In'buxners of the so-called 'gun" type, liquid fuel is delivered underrelatively high pressure to` a nozzle from which it is forciblydischarged through a relatively small nozzle aperture into `thevcombustion chamber of a furnace, without pre-mixture with air but in theform of, finely divided atomized oil and in a generally coneshapedpath.l To provide a combustible mixture,` air is discharged into thecombustion chamber, usually under the forced draft of a motorv drivenair impeller, throughs lronduit surrounding the oil nozzle and openinginto the combustion chamber, the latter being otherwise sealed olf sothat substantially the entire air available for oombustion is deliveredthrough such conduit the nozzle'and is intended to intermingle with theatomized oil.

Referring to the drawings and more particularly to Fig. 1, the workingparts of the burner are supported by and mainly contained within abarrel like casing having a cylindrical body I1 and a tapered forwardend I9, this casing forming the air conduit through which air issupplied to the combustionchamber. The casing may be permanentlyinstalled with ,the forward end .of the tapered part i9 entered into andsealed I support, such as the upright standard o r plate' 23.` Thelatter has a curved top Aflange to which issecured the under forwardside of the cylinder portion il and has a foot 2,'l secured to thefloor.

about 1 wiuun the casing (the detail-construction or Y Figs. 5 and 6)arecontained the principal working parts of theburner, including (Fig.l) the oil nozzlez. the loil delivery pipe) I the sparking 'electrodesStand other elecair impeller 31, these being so related to 'each otherand'to a supporting sleeve 39 telescopiealiy the electric motor 35 andthe iltting the rear end or breech of the cylindrical portion I1 thatthey are carried by the sleeve as a unit and, as a unitary assemblage,may be readily withdrawn from or replaced in the casing at Herein suchunitary assemblage comprehends also the transformer 4| depending belowthe casing together with its electrical connections to the motor and tothe sparking electrodes, as well as the oil pump 43 and associatedpressure regulating valve 45 and strainer 41. The pump, valve andstrainer are carried at the rear of the casing by a bracket 49 connectedto the supporting sleeve 39.

having a contracted air delivery mouth for the/ purpose hereinafterdescribed.

The casing of the motor is supported by the sleeve through a pluralityof equallyspaced arms 52 (herein four in number) formed integrally withthe sleeve and extending part way radially inward, each arm carrying alaterally extending lug 53 bolted to a boss on the motor casing'. Theshape and arrangement of such supporting lugs are best indicated inFigs. 3, 7 and 8. Thisarrangement suspends the motor on the supportingsleeve in overhanging relation within the barrel I1 just beyond thecontracted mouth of the sleeve, leaving an annular space between thecylindrical casing and the motor to serve as a part of the air conduit.'Ihe faces 54 of the arms 52 which confront the closely adjacentrotating blades ofthe air impeller serve as air deflecting surfaces, asis hereinafter more fully explained.

The forward end of the motor casing is provided with a central boss 55into which the rear end of the oil delivery pipe 3| is threaded and bywhich it is supported and maintained in coaxial vrelation tp the mouthof the conduit, the importance of which will be understood fromsubsequent explanation. The motor is provided with a shaft 51, the rearend of which (Fig. 1) .protrudes from the motor casing and has removablyconnected to it, as by the set screw 59, the sleeve-like hub 6I of theair impeller 31, which latter herein is of the propeller orpitched-blade type of a novel construction to be described.

To additionally support the pump, valve and strainer, the sleeve 39 hasformed integrally there with a rearwardly extending supporting bracket49, the upright part of which carries a sleeve 63, the bore of which isaccurately machined to bring it in axial alignment with the motor'shaft.

Within the sleeve is a barrel-likeV casing comprising the body of theoil pump 43 held therein by a set screw 65. The

sure relief valve 45` and oil strainer 41 (Fig. 2)

may, be separate from the pump but herein they are formed integrallywith the pump casing so that they are supported as a unit by the bracketremovably usual pres- To drive the oil pump, the latter has a Aforwardlyprotruding' driving shaft 61, the end of which (Fig. 1) enters the borewithin the fan boss 6| and faces but is spaced from the end of the motorshaft 51. A resilient driving connection is 1nterposed betweenthe motorand pump shafts, this being provided by means of a coiled spring 69 heldloosely within the fan boss bore in the space between the ends of thetwo shafts. This spring terminates at one end in a longitudinallystraight piece 1I which lies loosely within a longitudinal key-way orslot in the motor shaft and at the opposite end in'a transversely bentpiece 13'which lies within an vopen slot cut transversely in theopposing end of the pump shaft.

When the parts are thus assembled, the motor i's connected to drive thepump through the resilient connection, the spring acting to open more orless when the motor starts, thereby equalizing the pump load on themotor and cushioning the effect of the pump load in starting the motor.

This relationship permits the parts to be withdrawn as a unitarystructure from the casing, leaving the assemblage of the motor, fan andpump intact. The pump assemblage and the spring 69, with the unit eitherremoved or in place within the casing, may be withdrawn from itsassociation with the other parts by loosening the set screwand-withdrawing the pump from the sleeve 63 and may be reassembled withequal ease. The spring 69 provides a resilient driving connectionbetween the pump and the motor which is protectively enclosed by thesurrounding Walls of the fan boss 6I but may be readily removed orslipped into place in separating or assembling the parts. This`assemblage of the pump, fan and motor supported by the sleeve 39furthermore provides and maintains an accurate Yalignment of the motorand pump shafts.

Referring now to the-path of the oil to the nozzle, the strainer 41(Fig. 2) has connection to the usual tank or main source of oil supply(not herein shown) through the feed pipe 15, the oil passing up to thesuction side of the pump and thence through the delivery side of thepump to the pressure relief valve 45 through passages contained withinthe casing (not herein shown). The pump has the usual bypass leadingback to the main tank through pipe 11. Both the tank pipes 15 and 11 areprovided with separable pipe connections by means of which the pump, andstrainer may be quickly disconnected from the tank pipes, leaving theworking unit free for removal from the burner casing.

The oil entering the pressure relief valve from the pump leaves thevalve through the oil delivery pipe 19 which (see Fig. l) extendsforwardly through an opening in the walls of the supporting sleeve 39,thence through. the annular space between the motor 35 and barrel I1into the tapered forward end I9 of the casing, where it has a connection8| with the hollow interior of the oil delivery pipe 3|. The latter hasa bore of substantial diameter so as to `provide a self-containedchamber of appreciable capacity, the reserve amount of cil containedWithin the bore of the pipe tending to maintain a cooling effect on thenozzle and prevent carbonization of the oil thereat.

Referring now to the transformer and electrical connections, thetransformer on the sleeve 39 by means of a U-shaped suspension bracket83 (Figs. 2, 3 and 7). This bracket has a fiat bottom which extendstransversely across and is fastened to the flat top of 4I is alsosupported the transformer at the rear thereof. The upright y VaiasfistTo permit the insertion of the supporting sleeve 39 carrying theattached bracket 83 into the barrel casing, the rear end of the casing(as best seen in Figs. 5 and 6) has its Walls cut out to form anarc-shaped recess 85 of a suicient size to admit the side arms of thebracket 83.

Readily separable electrical connections from the transformer to thesource of power are provided in the form of stud connections 81 (Figs. land 3), herein three in number, protruding from the front lower end ofthe transformer and slidably engaging with corresponding jacks 89positioned in an insulating block 9| supported in thestandard 23. Theblock 9| forms an outlet for the junction box 93 through which the jacksare permanently connected to the cable 95 leading to a source ofelectric current. When the unit with the transformer is withdrawn fromthe casing, contact between the studs and jacks is automatically broken,and when'the unit is reinstalled such contact is automatically made.

From the stud terminals 81 suitable connection is made directly to themotor 35 by the insulated motor leads 91 passing upwardly through theinsulating block 99, the latter extending over and beyond the top frontedge of the transformer.

The transformer secondary has connection to the sparking electrodesthrough two highly insulated cables which also pass upwardly throughopenings in the insulating block 99 (Figs. 1 and 3). The mounting of theelectrodes 33 and the secondary connections thereto present certainnovel features of improvement.

As best seen in Figs. 1, 3 and 4, the electrodes are supported at theirrear ends by a porcelain insulating disk |03. The latter is mounted onand coaxial with the oil delivery pipe 3|, being provided with a hubwhich fits over the pipe and is held in abutting relation to the motorboss 55 by means of the clamping nut |05. The electrodes 33, whichherein are bare metallic conducting rods, are secured in the disk in thespaced relation indicated in Fig. 3, extending forwardly therefrom andsuspended thereby, their ends being brought into the desired sparkingrelation to each other and to the nozzle 29.

The rear of each electrode rod is clamped to a portion of the disk andextends through the latter, and at the back of the disk (Fig. 4) hassuitable electrical connection to a terminal |01 on the secondary cable|0|.

The use of the porcelain supporting disk near the rear end of the oilsupply tube permits the use of relatively small, light electrode rodswithout the necessity of other supporting devices which tend tointerfere with the designed air flow through the tapered conduit |9 andwithout the need of porcelain or other insulating sleeves thereon. Thedisk (as best seen in Fig. 3) maintains the unnsulated exposed surfacesof the electrodes and connections in such spacial relation as to provideboth the required air gap separation and the required minimum ofcreepage surface from such uninsulated surfaces to the nearest groundedconductive element of the apparatus. The use of the porcelain diskfurthermore provides a heat baffle protecting the motor from thelradiant heat of the combustion chamber, its white color aiding inreflecting the heat instead of absorbing and transmitting it to themotor at the rear. I

To permit removal of the motor and electrode connections with thetransformer and other parts of the unit, the bottom of the barrel casing|1 is provided with a longitudinal slot |09 (seen best in Fig. 6)extending forwardly from the cut-away recess 85 for a suillcientdistance to acconnnodate the insulating block 99.

To provide for the' closure of the bottom of the air conduit where itotherwise would be opened by such slot in front of the contractedmouth-of the supporting sleeve 39, the transformercarries means forclosing such slot. Herein this is conveniently provided by theinsulating block 99vwhich has a rearward extension the at top of whichis secured to the top of the transformer casing and abuts at its rearend against the front edge of the bracket 83. The insulating block, itwill be observed, is of rectangular shape in plan corresponding td theshape of the slot |09. Herein both the forward end and the extension ofthe insulating block are shown as provided with beveled sides (as bestseen in Fig. 3) which have a sliding fit in the correspondingly beveledside walls of the slot |09 (Figs. and 6) so that, when the unit isentered into place within the barrel, the block completely fills theslot and closes up the bottom of the air conduit thereat. i

The described construction greatly simplified, improves the Servicing ofinstalled burners, and reduces expense attendant thereon. Trouble in theoperation of burners ofthis class has heretofore required the presenceof an experienced service man at the point where the burner isinstalled. After locating the cause of the trouble, which in itself mayrequire considerable time, the fault must be corrected. This usuallyrequires dismantling the burner or parts thereof and replacing a faulty4part, if such part is at hand, or sending back to the service stationfor a duplicate part. This not only interrupts the operation'of theburner for periods of greater or lesser length, during which time theuser of the burner is deprived of possibly greatly needed heat, but alsoadds both to the expense and annoyance incidental to servicing.

f The described construction not only provides an extremely compactassemblage, but one in which these disadvantages of service are in largepartavoided. Where trouble arises in the operation of the burner andtheservice station has been notifie-d, the trouble may be remedied almostimmediately by an inexperienced service representative.

The latter, by the two pipe connections to in a very few minutes oftime, remove the entire assembledl unit from the permanently installedpart ofthe burner casing by sliding it back and out of the rear of thecasing. The unit removed may then, in an equally short time, be replacedby sliding in through the rear or breech of the casing another duplicateassembled unit brought with him for that purpose,- thereby permittingthe burner to resume operation in the least possible time afternotification has been received of burner trouble. The entire removedassembled unit is then taken back to the service station for inspectionand such repair as may there be found necessary. This permits the promptcorrection of burner troubles at a minimum expense, since the laborrequired at the point of instal lationfor removingand replacing the unitis relatively inexpensive.

It will be observed that the assembled unit when removed presents theparts all exposed for complete inspection so that they may be readilyexamined at thelservice station or at the point of installation if, forany reason, servicing seems there desirable.

Referring now to the construction of the air impeller, which is bestshown in Figs. 9 to 12, inelusive, the fan comprises a series of thin,light,

' metallic blades 31 (herein six in number) approximately iiat butslightly concaved toward the air delivery side of the fan, each bladebeing of generally triangular shape with an outer arcshaped edge.

Each blade has at the inner and outer ends of one edge a small cornerflange H3 bent at right angles, by means of which anges the blade ispivotally'mounted on a pin or small rod H5 and on which it is held bythe small disk-shaped cap piece ill fixedly secured on the end of thepin. Each rod is iixedly secured to the fan hub Bi and projectsoutwardly therefrom but is also pitched somewhat forwardly in thedirection of air delivery.

A torsion spring H9 encircles each pin having one end xed to the pin andthe other end extending over and lying against the face of the adjacentfan blade so that normally when the fan is at rest the blades are urgedby the light pressure of the spring in a direction causing them toassume a closed position, or that shown in Figs. 9, 11 and 12, in whichposition they are each maintained by the small stop finger IZIprojecting from the lower end of the free side of the blade. In thedescribed relationship this nger encounters and is stopped by thepivoting pin H5 of the next adjoining blade.

The pivoted edge of each blade extends somewhat beyond the pivoting rddH5, and, when the. blades are in closed position, this extension isthere overlapped by the free edge of the next adjoining blade.Accordingly, when the fan is at rest and the blades closed, the latterform a substantially continuous closure in the general form of atruncated cone substantially closing the contracted mouth of the sleeve39, as best seen in Fig. 9, there being left between the edges of theblade and the mouth of such closure only a reasonable mechanicalclearance to permit the rotation of the fan and the subsequent resultingopening movement of the blades.,

When the fan` is started into rotation, however, the forward pitch ofthe pivotal axes of the blades causes the latter to move undercentrifugal force about the pivot pins and to open up against theopposing pressure of the springs H9 into some such position as isrepresented in Fig. 10. This opening movement continues as the speed ofrotation increases, until either positively arrested or until the centerof gravity of each blade reaches its maximum radial distance from theaxis of rotation. As soon as the open- Ving movement of the blades hasbeen initiated under centrifugal force, it is further aided by therc-action of the air across which the blades are then cutting. The Wallsof the air conduit within the sleeve are rearwardly flared to permit therequired opening movement of the blades.

'I'he working pitch of the blades and the resulting capacity of the fanfor air delivery are dependent on the extent of this opening movement.This may be predetermined and the air supply for the burner definitelyfixed by the simple use of an adjustable blade stop. This is hereinprovided 4by means of the sleeve |23 which is adjustably threaded on theoutside of the fan hub Bi and has its forward edge presented to the stopfinger i2! of each blade, as shown in Fig. 10. The stop |23 may beadjusted to any desired position lengthwise the threaded portion of thefan hub and there held xed by the set screw |25, thereby providing ameans whereby the opening of the blades may be adjusted to any pointbetween zero opening and maximum. 'I'he air supply for the burner maytherefore be pre-adjusted by the adjustment of the fan alone and Withoutthe disadvantageous use of any valve or shutter extraneous to the fan.

The use of self-closing air impeller blades provides the importantfunction of automatically stopping further passage of cold air into thefurnace as soon as the burner stops and as soon as the fan ceases tofunction in creating its forced draft. When the fan is at rest iteffects a substantial closure of the air conduit and automatically sealsoif the furnace from the entrance of cold air, whether induced by thenatural draft of the chimney or otherwise, thereby protecting the wallsof the combustion chamber and the furnace from the chilling effect ofsuch cold entering air and conserving the heat previously imparted tosuch walls.

'Ihe use of a propeller type of fan with pitched blades provides asmooth, even delivery of the air free from pulsations which arecharacteristic of the so-called Sii-roc0 fan or similar centrifugal fansof the radial blade type. The adjustment of the air supply by varyingthe capacity of the air impeller itself further avoids thoseirregularities and pulsations in the air flow which are characteristicof the employment of shutters or valves used for throttling the airsupply within an amount which is less than the capacity of the airimpeller to carry.

'I'he disclosed method of air regulation further eliminates much of thenoisy operation, which is characteristic of former methods ofvalve-controlled air regulation, and also permits the fan to run underefiicient conditions for all varying air supplies to which it may beadjusted with an increased efficiency and reduced expenditure of power.

A further advantage of the air impeller herein described lies in thefact that the starting load on the burner is relatively small when thefan blades are closed, so that the motor is given opportunity to get upto speed while the blades are opening and before its full load comes onthe motor, thereby correspondingly lowering the starting torque requiredof the motor. A further advantage in the functioning of the burner isalso had in that in starting up the burner the full supply of air ismomentarily retarded, resulting in an initially richer and more readilycombustible mixture at the nozzle, thereby insuring greater certainty ofignition the instant the burner starts into operation.

The efiiciency of combustion and the desirable form, position and othercharacteristics of the resulting ame are to a large extent dependent on.the relative movement of the air and oil in leaving the mouth of theair conduit and entering the combustion chamber and on the point atwhich intermingling of the air and oil and resultant combustion takesplace.

It has been found that to provide a fat smokeless flame evidencingcomplete combustion, the air delivered to the air impeller shouldadvance progressively through the air conduit with a helical rotarymovement and emerge from the mouth of the conduit as an air bodyrotating under a high momentum, free from the effect of turbulence orother disturbing factors which interfere with its vertical movement, andassuming the -shapedsprayi of atomized-oil, and the expanding body ofair may bebroughtrinto` such coincidence ata point inadvanceof the-mouthof the 'conduit that a complete intermingling of the air .and oil .takesplacewithqsubstantially no tendency for thedispersion of foil particles:outside of the enveloping and expanding air helix, thereby eliminating4themaincause of a Asmoky llame, and with substantially v-no tendencyforthe dispersion of any substantial amount of air required forcombustion'outside ofthev expanding cone of oil spray therebyeliminating themain cause for the formation of thin `tcrch-lile'flames.lThis tends to produce a fat, lWell dened and developed smokeless ame,havingan unvarying and substantially xed position.

4We' have 1 found that'to secure the required movement of the air'inrelation to theV oil spray, not 4only should there :be prevented the.turbulence of 'theair arisingy throughthe presence of obstructions,such as mechanical 'baffles or turbulators, at .or near the certainother air conditionsshould be maintained which have heretofore been lostsight of butwhich arebest reached .by-the cooperation of agenciesembodying the"principles characteristic of the construction hereindescribed.

. One condition which should be maintained, and the absence'oflwhichinterferes with the required coordinationbetweenthe oil and air bodieson emergence from the `fc'onduit, is a smooth, even flow oftheairfrom'the conduit mouth free from pulsations ora flutter.V Another`condition, is a substantiallyluniformf density of the air at all pointsinthe periphery of the progressively rotating air body where itleavesthe mouth of the conduit, Bothof these conditions are promotedbythe use ofsthewpropeller type of fan, and particularly whereitscapacity is adjusted by adjust- `ing the pitch of *the-blades; Thedelivery of the air is then unaffectedby variations in the area of theair intake and is proportional to the open- ,ings of theblades, sothateach blade impels the air ina smooth',` steadyow'of uniformperipheral density. t .i

Another condition is the `maintenance of a proper relation at themouthof the conduit between thedensity or `pressure of the air at theperiphery of the\,rotating yairbody and its density or pressure aroundand about the nozzle. v

Initial combustion'y should take place and should be maintained at apoint well in advance of the nozzle where theairhas become heated andhas had `opportunity to undergo a substantial expansion. Otherwise a.noisy, imperfect combus-.tionl may follow.,y with an; irregular,wavering nameswww s: l f `ff'If thefflam'e `is `clrfawnflback against orclose to thelnozzle, `the latteraabecomes overheated and'troubles-fro'mfcarbonization arise. If the flame iSallOWedftO-iloat toofar away from the nozzle it `tends to ybecome extinguished, so that theundesirablepract-icctof'wrnaintaining a continuous ignition .atithe'sparking;,electrodes must be followedw" l i l f The'mai-ntenanceii'o nunmalv combustion at the l desired pointisiniiuencedto a large extent by air` pressure. conditionslqgf-,The rotary movementoftheair atiand'in front 'of the mouth of the air mouthof the` conduit,but

conduit tends to create a vacuum or subnormal pressure along the axisofthe air helix. Thi is due to the fact thattthe rotary movement, helair induces an air uw' oating away from the positln a is desired butshould be inapprecia A y ,toy 'void drawing s ,pg tends to create such`par al' vacuum the Vicinity of thefnozzl away from its desiredpo wardthe nozzle, dist it is desired to maintain to provide such a balanbetween th1 progres;

sive and lrotary movement vv,Jvfwtlife" airf'b Ay which will bemaintained undervaryingfconditionsof air supply, that a nonfdistinbingflame 'relation is established at the axiswofthe air` helix yandparticularly about the nozzl y,

In the described 'construction',A when `theburner is started andtheairimpeller reaches" normal speed (rotating in 1a` counter-clockwisedirection as viewed from the'rear andasjindicated bythe arrows in Figs.2 and' 3), [freeedges of 'the blades cut across' thejairfproducin'g'very intense rotary .movement ofthef'air in'which Athe yairfis forcedoutward towardtl'ie peripheryothe con-'- duit. The fan 'thus providesthejgagency ,for the rotation of the air deliveredythroughlthefconduit,

and for any given speedof thefa'nsuch rotation is substantiallyvconstant;` j It, will falso: ybe@,seen that the tapered interi'orjo'f`the .endof that part of the conduit surrounding the nozzle isV free`from any mechanical obstructions whichl interfere with the rotarymovementestablished by the fan.

To induce the required 'progressive' lmovement of the air which' is'thsrotated byfthe fan and to' establish the required balance between itsrotary andprogressive` movement is kone function herein of the airdeflecting'surfac`esv 5.4 on the, arms 52 which, it will be observed,`lie immediately in front of the fan and'project radially Yinward acrossthe annular path ofgthe yrotating ,airbody as'it leaves-,the fan.Ifwthe'numbe'r or"effec` tiveness of such cut-fofffmembers'is increased,"i

the rotary movement of 1 the air is diminished and its progressivemovement further increased.y VIf such number or eiectivenessis lessened,the

the time the lair helix; emerges `from themouth of the conduit.Inval,burnerofthesize and `air dimensions, indicated, "four 'of suchcutoffifaces have been; `fourmi .togstfabiishztndesired relation betweenthe .progressive and [rotary movements rotary air movementyisincreasedan'd lthe'pro- `capacity hereinl s ho'wn ,and ,(with` arms ofthe to prevent .an appreciable yvacuum l or backward ame ,suction at"the nozzleE whi required highf` momentum 'rotary n, at the conduitmouth.` fI.

Features` of the yairy impe ler`r and ,automatic shutter, independent,of their cooperative ,t relationto vthe features l,of ailiquidfuelburnemare separately l. claimed in' our copending divisionalapplication, serial No. 84,694,1i1eduun 11 y19st;

yieniirigtne 12: Insieme@ While we have herein shown and described forshown, all without departing from the spirit of the invention.

We claim: Y

1. A liquid fuel burning apparatus having an air conduit for deliveringair to a combustion chamber, a motor in said conduit, a supportingmember for the motor adapted to be installed in or removed from saidconduit, said member having arms connected to and supporting the motor in overhanging relation from said member but leaving an air admissionpassage to the air conduit, a nozzle in said conduit carried by saidsupporting member for delivering liquid fuel to said combustion chamber,and an air impeller axially aligned with and driven by said motoroperatively mounted in said air conduit and also connected to saidsupporting member.

2. In a liquid fuel burning apparatus having fuel and air supply meansand a tubular air conduit, the combination, of a motor, fuel deliverynozzle and sparking electrodes all positioned within said conduit, aremovable structure on which said motor, nozzle and electrodes areassembled in operative relationship to each other and o'n which saidstructure as an assembled unit they may be installed within or withdrawnfrom said conduit at will through the rear thereof, and a transformeroutside of said conduit electrically connected to said electrodes andattached to said structure by a connection passing through the walls ofsaid conduit, the latter being longitudinally slotted to permit thewithdrawal of said motor, fuel delivery nozzle and sparking electrodesand the removal of the attached transformer.

3. In a liquid fuel burning apparatus having fuel supply means, thecombination of a tubular air conduit provided with an air dischargeopening at one end and an opening at theoppcsite end, a motor, an airimpeller driven thereby and a fuel 'delivery nozzle all positionedwithin said conduit, and a removable sleeve member fitting the oppositeend opening in said conduit'and constituting a removable structure onwhich said motor, air impeller and nozzle are supported and assembled inoperative-relationship to each other and on which sleeve member 'as anassembled unit they may be installed within or withdrawn from saidconduit at will through the opposite end 4. In a liquid fuel burningapparatus having fuel supply means, the combination of a tubular airconduit having a substantially Vstraight portion with an` air dischargeopening at one end and an opening at the opposite end, a motor, a fueldelivery nozzle supported by the motor\ near the discharge end of theconduit and an air impeller driven bythe motor near the opposite endthereof, and a removable structural member on which the -motor, airimpeller and nozzle are assembled in operative relationship to eachother and on which structure as an assembled unit they may be installedwithin or withdrawn from said conduit at will through the opposite endthereof, said structure being removably tted to said conduit to carrysaid motor, air impeller and nozzle in coaxial relationship thereto wheninstalled therein. k

5. In a liquid fuel .burning apparatus having fuel supply means, thecombination f a tubular air conduit provided with an air dischargeopening at one end and an opening at the opposite end, a motor, an airimpeller driven thereby and a fuel delivery nozzle all positioned withinsaid conduit, and a removable structural member on which-the motor, airimpeller and nozzle are assembled in operative relationship to eachother and on which member as an assembled unit they may be installedwithin or withdrawn from said conduit at will through the opposite endthereof, said structure being removably 'tted to said conduit to carrysaid motor, air impeller and nozzle in coaxial relationship to saidconduit when installed therein.

6. In a liquid fuel burning apparatus having fuel delivery means, thecombination of a tubular air conduit provided with an air dischargeopening at one end and an opening at the opposite end, a motor, a fueldelivery nozzle and an air impeller driven by said motor all positionedwithin said conduit, a removable structure on which said motor, nozzleand air impeller are assembled in operative relationship to each otherand on which said structure as an assembled unit they may be installedwithin or withdrawn from said conduit at will through the opposite endthereof, a pump outside of said conduit driven by said motor and carriedby said removablestructure in operative relationship to said motor andconnections for supplying liqiud fuel from said pump to said nozzle.

7. In a liquid fuel burning apparatus having fuel and air supply means,the combination of a tubular air conduit provided with an air dischargeopening at one end and an opening at the opposite end, a motor, a fueldelivery nozzle and sparking electrodes all positioned within saidconduit, a removable structure on which said motor, nozzle andelectrodes -are assembled in operative relationship to each other and onwhich structure as an assembled unit they may be installed within orwithdrawn from said xconduit at will through the opposite end thereof,and a transformer also attached to and carried by said structure inassembled operative relationship to said sparking electrodes.

8. -In a liquid fuel burning apparatus having fuel supply means, thecombination of a tubular air conduit provided with an air dischargeopening at one end and an opening at the opposite end, a motor, an airimpeller driven thereby, a fuel delivery nozzle and sparking electrodesall positioned within said conduit, and aremovable structure on whichsaid motor, air impeller, nozzle and electrodes are assembled inoperative relationship to each other and on which structure as anassembled unit they may be installed within or withdrawn from saidconduit at will through the opposite end thereof. l'

9. In a liquid fuel burning apparatus having fuel and air supply means,the combination of a tubular air conduit provided with an air dischargeopening at one end and an opening at the opposite end, a motor, a fueldelivery nozzle and sparking electrodes all positioned within saidconduit, and a removable structure on which said motor, nozzle andelectrodes are assembled in operative relationship to each other and onwhich structure as an assembled unit they may be installed within orwithdrawn from said conduit at will through the opposite end thereof. 1-10. A liquid fuel burning apparatus having means for delivering liquidfuel to a combustion chamber, an air delivery conduit for delivering airto said chamber, a motor for driving said fuel v duit when saidstructure delivery means, a rotatable structure having parts movable onand with relation to `said structure and of such size, shape andrelation as to serve as a substantial closure for said air conduit whensaid structure is at rest but movable in response to centrifugal forceto open said conis rotated, and a driving connection between saidstructure and motor for driving the former from the latter.

11. A liquid fuel burning apparatus having means for vdelivering liquidfuel to a combustion chamber, anair-gdelivery conduit for delivering airto said. chamber, amotor for driving said fuel delivery means,`arotatable structure having a plurality of `blades mounted to turn eachon an axis extending outwardly from but inclinedto the axis ofrotation-of said structure, the blades being of such size, shape andrelation as to form a substantial closure for said conduit, meansresponsive to centrifugal force on rotation of said structure for movingsaid blades to a conduit opening position, means foi` moving said bladesto a conduit closing position on the stoppage of rotation, and a drivingconnection between said structure'and the motor for driving the formerfrom the latter.

12. A liquid fuel burning apparatus having means for delivering liquidfuel to a combustion chamber, an air delivery conduit for delivering airto said chamber, a motor for driving said fuel delivery means, an airimpeller for forcing air through said conduit and comprising a rotatablesupport having blades movable relatively to the support, means formoving said blades tonormally provide a substantialvclosure for theconduit, means responsive to centrifugal force created by the rotationof the impeller for opening said blades to an air impelling position,and a driving connection between said impeller and the motor for drivingthe former from the latter.

13. A liquid fuel burning apparatus having means for delivering liquidfuel to a combustion chamber, an air delivery conduit for delivering airto said chamber, a motor for driving said fuel delivery means, a rotaryair impeller having impelling blades mounted each to turn on an axisextending outwardly from the axis of rotation of thev impeller, meansresponsive to centrifugal force following the rotation of said irnpellerto move said blades about their axes to augment their air impellingeffect, means effective on the stoppage of such rotation to move saidblades about their axes in an opposite direction, and a drivingconnection between said impeller and said motor for driving the formerfrom the latter.

14. A liquid fuel burning apparatus having a nozzle for the delivery ofliquid fuel to a combustion chamber, an air delivery conduit surroundingsaid nozzle for delivering. air to said chamber to be commingled withsaid fuel, a motor, a pump driven by said motor for forcing liquid fuelto said nozzles, a rotatable air impeller structure having bladesmovable on and with relation to said structure, serving as a substantialclosure for said air conduit when said structure is at rest but movableunder centrifugal force to open said conduit and impel the airtherethrough when said structure is rotated, and a driving connectionbetween said structure and the motor for driving the former from thelatter.

RALLSTON M. SHERMAN. JOHN CARLBERG. GEORGE R. NEUMANN.

